Methods of filling a set of interstitial spaces of a nanoparticle thin film with a dielectric material

ABSTRACT

A method of forming a densified nanoparticle thin film is disclosed. The method includes positioning a substrate in a first chamber; and depositing a nanoparticle ink, the nanoparticle ink including a set of Group IV semiconductor particles and a solvent. The method also includes heating the nanoparticle ink to a first temperature between about 30° C. and about 300° C., and for a first time period between about 1 minute and about 60 minutes, wherein the solvent is substantially removed, and a porous compact is formed; and positioning the substrate in a second chamber, the second chamber having a pressure of between about 1×10 −7  Torr and about 1×10 −4  Torr. The method further includes depositing on the porous compact a dielectric material; wherein the densified nanoparticle thin film is formed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/873,412 filed Dec. 7, 2006, the entiredisclosure of which is incorporated by reference.

FIELD

This disclosure relates in general to Group IV semiconductor thin films,and in particular to methods of filling a set of interstitial spaces ofa nanoparticle thin film with a dielectric material.

BACKGROUND

The Group IV semiconductor materials enjoy wide acceptance as thematerials of choice in a range of devices in numerous markets such ascommunications, computation, and energy. Currently, particular interestis aimed in the art at improvements in devices utilizing semiconductorthin film technologies due to the widely recognized disadvantages ofchemical vapor deposition (CVD) technologies. For example, some of thedrawbacks of the current CVD technologies in the fabrication ofsemiconductor thin films and devices include the slow deposition rates,which limit the cost-effective fabrication of a range of filmthicknesses, the difficulty in accommodating large components, highprocessing temperatures, and the high production of chemical wastes.

In that regard, with the emergence of nanotechnology, there is ingeneral growing interest in leveraging the advantages of these newmaterials in order to produce low-cost devices with designedfunctionality using high volume manufacturing on nontraditionalsubstrates. It is therefore desirable to leverage the knowledge of GroupIV semiconductor materials and at the same time exploit the advantagesof Group IV semiconductor nanoparticles for producing novel thin filmswhich may be readily integrated into a number of devices. Particularly,Group IV nanoparticles in the range of between about 1.0 nm to about100.0 nm may exhibit a number of unique electronic, magnetic, catalytic,physical, optoelectronic, and optical properties due to quantumconfinement and surface energy effects.

With respect to thin films compositions utilizing nanoparticles, U.S.Pat. No. 6,878,871 describes photovoltaic devices having thin layerstructures that include inorganic nanostructures, optionally dispersedin a conductive polymer binder. Similarly, U.S. Patent ApplicationPublication No. 2003/0226498 describes semiconductornanocrystal/conjugated polymer thin films, and U.S. Patent ApplicationPublication No. 2004/0126582 describes materials comprisingsemiconductor particles embedded in an inorganic or organic matrix.Notably, these references focus on the use of Group II-VI or III-Vnanostructures in thin layer structures, rather than thin films formedfrom Group IV nanostructures.

An account of nanocrystalline silicon particles of about 30 nm indiameter, and formulated in a solvent-binder carrier is given inInternational Patent Application No. WO20041B00221. The nanoparticleswere mixed with organic binders such as polystyrene in solvents such aschloroform to produce semiconductor inks that were printed on bond paperwithout further processing. In U.S. Patent Application Publication No.2006/0154036, composite sintered thin films of Group IV nanoparticlesand hydrogenated amorphous Group IV materials are discussed. The GroupIV nanoparticles are in the range 0.1 to 10 nm, in which thenanoparticles were passivated, typically using an organic passivationlayer. In order to fabricate thin films from these passivated particles,the processing was performed at 400° C., where nanoparticles below 10 nmare used to lower the processing temperature. In both examples,significant amounts of organic materials are present in the Group IVthin film layers, and the composites formed are substantially differentthan the well-accepted native Group IV semiconductor thin films.

U.S. Pat. No. 5,576,248 describes Group IV semiconductor thin filmsformed from nanocrystalline silicon and germanium of 1 nm to 100 nm indiameter, where the film thickness is not more than three to fourparticles deep, yielding film thickness of about 2.5 nm to about 20 nm.For many electronic and photoelectronic applications, Group IVsemiconductor thin films of about 200 nm to 3 microns are desirable.

Therefore, there is a need in the art for native Group IV semiconductorthin films of about 200 nm to 3 microns in thickness fabricated fromGroup IV semiconductor nanoparticles, which thin films are readily madeusing high volume processing methods.

SUMMARY

The invention relates, in one embodiment, to a method of forming adensified nanoparticle thin film. The method includes positioning asubstrate in a first chamber; and depositing a nanoparticle ink, thenanoparticle ink including a set of Group IV semiconductor particles anda solvent. The method also includes heating the nanoparticle ink to afirst temperature between about 30° C. and about 300° C., and for afirst time period between about 1 minute and about 60 minutes, whereinthe solvent is substantially removed, and a porous compact is formed;and positioning the substrate in a second chamber, the second chamberhaving a pressure of between about 1×10⁻⁷ Torr and about 1×10⁻⁴ Torr.The method further includes depositing on the porous compact adielectric material; wherein the densified nanoparticle thin film isformed.

The invention relates, in another embodiment, to a method of forming adensified nanoparticle thin film in a chamber. The method includespositioning a substrate; and depositing a nanoparticle ink, thenanoparticle ink including a set of Group IV semiconductor particles anda solvent. The method also includes densifying the nanoparticle ink intoa porous compact, wherein the solvent is removed; and spin coating aspin-on-glass material on the porous compact from about 3000 rpm toabout 4000 rpm. The method further includes heating the spin-on-glassmaterial to a first temperature between about 80° C. and about 250° C.,and for a first time period between about 1 minute to about 30 minutes;and heating the spin-on-glass material to a second temperature betweenabout 400° C. and about 600° C., and for a second time period betweenabout 30 minute to about 1 hour; wherein the densified nanoparticle thinfilm is formed.

The invention relates, in another embodiment, to a method of forming adensified nanoparticle thin film in a chamber. The method includespositioning a substrate; and depositing a nanoparticle ink, thenanoparticle ink including a set of Group IV semiconductor particles anda solvent. The method also includes densifying the nanoparticle ink intoa porous compact, wherein the solvent is removed; and depositing ahydrocarbon species on the porous compact, wherein the hydrocarbonspecies includes one of a terminal alkene group or a terminal alkynegroup. The method further includes heating the hydrocarbon species to afirst temperature between about 150° C. and about 300° C., at a pressureof between about 1 Torr and about an atmosphere; wherein the densifiednanoparticle thin film is formed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart that depicts processing steps for the formationof embodiments of Group IV semiconductor thin films using in situtreatment of a thin film during fabrication, in accordance with theinvention.

FIGS. 2A-2C depict the process of thin film formation from oxide coatedGroup IV semiconductor nanoparticles using in situ processing duringthin film fabrication, in accordance with the invention.

FIG. 3A and FIG. 3B show two embodiments of in situ processes forremoving an oxide coating from Group IV semiconductor nanoparticles, inaccordance with the invention.

FIGS. 4A-4C depict a Group IV semiconductor porous compact (FIG. 4A) anda Group IV semiconductor thin film (FIG. 4B) having interstitial spacesand the thin film after in situ treatment (FIG. 4C) to fill theinterstitial spaces, in accordance with the invention.

FIG. 5 shows an embodiment of an in situ process for filling theinterstitial spaces of a Group IV semiconductor thin film, in accordancewith the invention.

FIG. 6A and FIG. 6B depict a section of a Group IV nanoparticle thinfilm before surface passivation (FIG. 6A) and after surface passivation(FIG. 6B), in accordance with the invention.

FIG. 7 shows an embodiment of an in situ process for surface passivationof a Group IV semiconductor thin film.

DETAILED DESCRIPTION

Embodiments of thin films formed from native Group IV semiconductornanoparticles, and methods for making such thin films are disclosedherein. The photoconductive thin films result from coating substratesusing dispersions of Group IV nanoparticles to form a porous compact,which porous compact is processed to form a Group IV semiconductor thinfilm. Either during the fabrication of a Group IV semiconductor thinfilm from the porous compact, or subsequent to the fabrication of aGroup IV semiconductor thin film, in situ treatment may be done. Thefabrication process, as well as the in situ treatment is done in aninert environment. The in situ processing is done to ensure thelong-term stability and function of the fabricated Group IVsemiconductor thin films. In some embodiments, in situ treatment is doneto remove non-Group IV semiconductor material from the nanoparticle orthin film surfaces during thin film fabrication. In other embodiments,fluids are used during or subsequent to thin film fabrication in aninert environment to fill or essentially fill the interstitial spaces ina thin film with insulating material. Finally in other embodiments, insitu passivation of surfaces that are in fluid communication with theexternal environment may be done.

The embodiments of the disclosed thin films fabricated from Group IVsemiconductor nanoparticle starting materials evolved from theinventors' observations that by keeping embodiments of the native GroupIV semiconductor nanoparticles in an inert environment from the momentthe particles are formed through the formation of Group IV semiconductorthin films, that such thin films so produced have propertiescharacteristic of native bulk semiconductor materials. In that regard,such thin films are formed from materials for which the electrical,spectral absorbance and photoconductive properties are wellcharacterized. This is in contrast, for example, to the use of modifiedGroup IV semiconductor nanoparticles, which modifications generally useorganic species to stabilize the reactive particles, or mix thenanoparticles with organic modifiers, or both. In some suchmodifications, the Group IV nanoparticle materials are significantlyoxidized. The use of these types of nanoparticle materials produceshybrid thin films, which hybrid thin films do not have as yet the samedesirable properties as traditional Group IV semiconductor materials.

As used herein, the term “Group IV semiconductor nanoparticle” generallyrefers to hydrogen terminated Group IV semiconductor nanoparticleshaving an average diameter between about 1.0 nm to 100.0 nm, andcomposed of silicon, germanium, and alpha-tin, or combinations thereof.As will be discussed subsequently, some embodiments of thin film devicesutilize doped Group IV semiconductor nanoparticles. With respect toshape, embodiments of Group IV semiconductor nanoparticles includeelongated particle shapes, such as nanowires, or irregular shapes, inaddition to more regular shapes, such as spherical, hexagonal, and cubicnanoparticles, and mixtures thereof. Additionally, the nanoparticles maybe single-crystalline, polycrystalline, or amorphous in nature. As such,a variety of types of Group IV semiconductor nanoparticle materials maybe created by varying the attributes of composition, size, shape, andcrystallinity of Group IV semiconductor nanoparticles. Exemplary typesof Group IV semiconductor nanoparticle materials are yielded byvariations including, but not limited by: 1.) single or mixed elementalcomposition; including alloys, core/shell structures, dopednanoparticles, and combinations thereof 2.) single or mixed shapes andsizes, and combinations thereof, and 3.) single form of crystallinity ora range or mixture of crystallinity, and combinations thereof.

Group IV semiconductor nanoparticles have an intermediate size betweenindividual atoms and macroscopic bulk solids. In some embodiments, GroupIV semiconductor nanopartieles have a size on the order of the Bohrexciton radius (e.g. 4.9 nm), or the de Broglie wavelength, which allowsindividual Group IV semiconductor nanoparticles to trap individual ordiscrete numbers of charge carriers, either electrons or holes, orexcitons, within the particle. The Group IV semiconductor nanoparticlesmay exhibit a number of unique electronic, magnetic, catalytic,physical, optoelectronic and optical properties due to quantumconfinement and surface energy effects. For example, Group IVsemiconductor nanoparticles exhibit luminescence effects that aresignificantly greater than, as well as melting temperatures ofnanoparticles substantially lower than the complementary bulk Group IVmaterials. These unique effects vary with properties such as size andelemental composition of the nanoparticles. For instance, as will bediscussed in more detail subsequently, the melting of germaniumnanoparticles is significantly lower than the melting of siliconnanoparticles of comparable size. With respect to quantum confinementeffects, for silicon nanoparticles, the range of nanoparticle dimensionsfor quantum confined behavior is between about 1 nm to about 15 nm,while for germanium nanoparticles, the range of nanoparticle dimensionsfor quantum confined behavior is between about 1 nm to about 35 nm, andfor alpha-tin nanoparticles, the range of nanoparticle dimensions forquantum confined behavior is between about 1 nm to about 40 nm.

Regarding the terminology of the art for Group IV semiconductor thinfilm materials, the term “amorphous” is generally defined asnon-crystalline material lacking long-range periodic ordering, while theterm “polycrystalline” is generally defined as a material composed ofcrystallite grains of different crystallographic orientation, where theamorphous state is either absent or minimized (e.g. within the grainboundary and having an atomic monolayer in thickness). With respect tothe term “microcrystalline”, in some current definitions, thisrepresents a thin film having properties between that of amorphous andpolycrystalline, where the crystal volume fraction may range between afew percent to about 90%. In that regard, on the upper end of such adefinition, there is arguably a continuum between that which ismicrocrystalline and polycrystalline. For the purpose of what isdescribed herein, “microcrystalline” is a thin film in whichmicrocrystallites are embedded in an amorphous matrix, and“polycrystalline” is not constrained by crystallite size, but rather athin film having properties reflective of the highly crystalline nature.

With respect to process step 110 of FIG. 1, the Group IV semiconductornanoparticles may be made according to any suitable method, several ofwhich are known, provided they are initially formed in an environmentthat is substantially inert, and substantially oxygen-free. As usedherein, “inert” is not limited to only substantially oxygen-free. It isrecognized that other fluids (i.e. gases, solvents, and solutions) mayreact in such a way that they negatively affect the electrical andphotoconductive properties of Group IV semiconductor nanoparticles.Additionally, the terms “substantially oxygen-free” in reference toenvironments, solvents, or solutions refer to environments, solvents, orsolutions wherein the oxygen content has been substantially reduced toproduce Group IV semiconductor thin films having no more than 10¹⁷ to10¹⁹ oxygen per cubic centimeter of Group IV semiconductor thin film.For example, it is contemplated that plasma phase preparation ofhydrogen-terminated Group IV semiconductor nanoparticles is done in aninert, substantially oxygen-free environment. As such, plasma phasemethods produce nanoparticle materials of the quality suitable formaking embodiments of Group IV semiconductor thin film devices. Forexample, one plasma phase method, in which the particles are formed inan inert, substantially oxygen-free environment, is disclosed in U.S.patent application Ser. No. 11/155,340, filed Jun. 17, 2005; theentirety of which is incorporated herein by reference.

In reference to step 120 of process flow chart 100 shown in FIG. 1, oncethe preparation of quality Group IV semiconductor nanoparticles having adesired size and size distribution have been formed in an inert,substantially oxygen-free environment, they are transferred to an inert,substantially oxygen-free dispersion solvent or solution for thepreparation of embodiments dispersions and suspensions of thenanoparticles; or preparation of an ink. The transfer may take placeunder vacuum or under an inert, substantially oxygen-free environment.In terms of preparation of the dispersions, the use of particledispersal methods such as sonication, high shear mixers, and highpressure/high shear homogenizers are contemplated for use to facilitatedispersion of the particles in a selected solvent or mixture ofsolvents. For example, inert dispersion solvents contemplated for useinclude, but are not limited to chlorofomm, tetrachloroethane,chlorobenzene, xylenes, mesitylene, diethylbenzene, 1,3,5triethylbenzene (1,3,5 TEB), and silanes, and combinations thereof.

Various embodiments of Group IV semiconductor nanoparticle inks can beformulated by the selective blending of different types of Group IVsemiconductor nanoparticles. For example, varying the packing density ofGroup IV semiconductor nanoparticles in a deposited thin layer isdesirable for forming a variety of embodiments of Group IVphotoconductive thin films. In that regard, Group IV semiconductornanoparticle inks can be prepared in which various sizes ofmonodispersed Group IV semiconductor nanoparticles are specificallyblended to a controlled level of polydispersity for a targetednanoparticle packing. Further, Group IV semiconductor nanoparticle inkscan be prepared in which various sizes, as well as shapes are blended ina controlled fashion to control the packing density.

Additionally, particle size and composition may impact fabricationprocesses, so that various embodiments of inks may be formulated thatare specifically tailored to thin film fabrication. This is due to thatfact that there is a direct correlation between nanoparticle size andmelting temperature. For example, for silicon nanoparticles between thesize range of about 1 nm to about 15 nm, the melting temperature is inthe range of between about 400° C. to about 800° C. versus the meltingof bulk silicon, which is 1420° C. For germanium, nanoparticles of in acomparable size range of about 1 nm to about 15 nm melt at a lowertemperature of between about 100° C. to about 400° C., which is alsosignificantly lower than the melting of bulk germanium at about 935° C.Therefore, the melting temperatures of the Group IV nanoparticlematerials as a function of size and composition may be exploited inembodiments of ink formulations for targeting the fabricationtemperature of a Group IV semiconductor thin film.

Another example of what may be achieved through the selectiveformulation of Group IV semiconductor nanoparticle inks by blendingdoped and undoped Group IV semiconductor nanoparticles. For example,various embodiments of Group IV semiconductor nanoparticle inks can beprepared in which the dopant level for a specific thin layer of atargeted device design is formulated by blending doped and undoped GroupIV semiconductor nanoparticles to achieve the requirements for thatlayer. In still another example are embodiments of Group IVsemiconductor nanoparticle inks that may compensate for defects inembodiments of Group IV photoconductive thin films. For example, it isknown that in an intrinsic silicon thin film, oxygen may act to createundesirable energy states. To compensate for this, low levels of p-typedopants, such as boron difluoride, trimethyl borane, or diborane, may beused to compensate for the presence of low levels of oxygen. By usingGroup IV semiconductor nanoparticles to formulate embodiments of inks,such low levels of p-type dopants may be readily introduced inembodiments of blends of the appropriate amount of p-doped Group IVsemiconductor nanoparticles with various types of undoped Group IVsemiconductor nanoparticles.

Other embodiments of Group IV semiconductor nanoparticle inks can beformulated that adjust the band gap of embodiments of Group IVphotoconductive thin films. For example, the band gap of silicon isabout 1.1 eV, while the band gap of germanium is about 0.7 eV, and foralpha-tin is about 0.05 eV. Therefore, formulations of Group IVsemiconductor nanoparticle inks may be selectively formulated so thatembodiments of Group IV photoconductive thin films may have photonadsorption across a wider range of the electromagnetic spectrum. Thismay be done through formulations of single or mixed elementalcomposition of silicon; germanium and tin nanoparticles, includingalloys, core/shell structures, doped nanoparticles, and combinationsthereof. Embodiments of such formulations of may also leverage the useof single or mixed shapes and sizes, and combinations thereof, as wellas a single form of crystallinity or a range or mixture ofcrystallinity, and combinations thereof.

Still other embodiments of inks can be formulated from alloys andcore/shell Group IV semiconductor nanoparticles. For example, it iscontemplated that silicon carbide semiconductor nanoparticles are usefulfor in the formation of a variety of semiconductor thin films andsemiconductor devices. In other embodiments, alloys of silicon andgermanium are contemplated. Such alloys may be made as discrete alloynanoparticles, or may be made as core/shell nanoparticles.

After the formulation of an ink, the steps of depositing a thin film ofGroup IV semiconductor nanoparticles 130, and fabricating the film intoGroup IV semiconductor thin film using in situ processing 140 are done.In step 130 of FIG. 1, using an embodiment of an ink formulation, a thinfilm of Group IV semiconductor nanoparticles is deposited on a solidsupport, which thin film is referred to as a green film or porouscompact. It is contemplated that a variety of deposition techniques aresuitable for the deposition of the dispersion of Group IV nanoparticleson a substrate. For example, but not limited by, various embodiments ofink formulations may be suitable for use with roll coating, slot diecoating, gravure printing, flexographic drum printing, and ink jetprinting methods, or combinations thereof.

In one aspect of in situ processing, embodiments of Group IVsemiconductor nanoparticles are coated with an oxide layer. Such acoating may be useful for dispersion of the nanoparticles in selectedsolvents, as well as for promoting stability during storage either asbulk solid or in ink formulations. In order to fabricate Group IVsemiconductor thin films from such coated Group IV nanoparticle inkdispersions, the coating is removed using in situ processing during thinfilm fabrication. For example, a rendering of the processing of coatedGroup IV semiconductor nanoparticles is schematically depicted incross-sections thin films in FIGS. 2A-2C, which are renderings for thepurpose of highlighting concepts, and are not meant as actualrepresentations of the thin film morphologies of embodiments of Group IVsemiconductor thin films disclosed herein.

In FIG. 2A, a porous compact 17 deposited using Group IV semiconductornanoparticles and having a coating layer 15 around nanoparticles 16 isshown. During the processing of embodiments of porous compact 17 to thinfilm 19, in situ processing may be done to remove the coating 15,allowing a porous compact 18 of Group IV nanoparticles to be formed, asshown in FIG. 2B. In FIG. 2C, a Group IV semiconductor thin film 19having known properties is formed from the Group IV semiconductor porouscompact 18.

In FIGS. 2A-2C, a substrate 10, upon which a first electrode, 14, andoptionally an insulating layer 12 between the substrate 10 and electrode14 are deposited is shown. For the fabrication of some embodiments of athin film 19, substrate materials may be selected from silicondioxide-based substrates. Such silicon dioxide-based substrates include,but are not limited by, quartz, and glasses, such as soda lime andborosilicate glasses. Silicon substrates are also considered assubstrates for the formation of a thin film 19, where a range of siliconsubstrates, such as prime grade to metallurgical grade are useful forfabricating a variety of embodiments of thin film 19. For thefabrication of other embodiments of a thin film 19, flexible stainlesssteel sheet is the substrate of choice, while for the fabrication ofstill other embodiments of thin film 19, the substrate may be selectedfrom heat-durable polymers, such as polyimides and aromaticfluorene-containing polyarylates, which are examples of polymers havingglass transition temperatures above about 300° C. The first electrode 14is selected from conductive materials, such as, for example, aluminum,molybdenum, chromium, titanium, nickel, and platinum. For variousembodiments of photoconductive devices contemplated, the first electrode14 is between about 10 nm to about 1000 nm in thickness. Optionally, aninsulating layer 12 may be deposited on the substrate 10 before thefirst electrode 14 is deposited. Such an optional layer is useful whenthe substrate is a dielectric substrate, since it protects thesubsequently fabricated Group IV semiconductor thin films fromcontaminants that may diffuse from the substrate into the Group IVsemiconductor thin film during fabrication. When using a conductivesubstrate, the insulating layer 12 not only protects Group IVsemiconductor thin films from contaminants that may diffuse from thesubstrate, but is required to prevent shorting. Additionally, aninsulating layer 12 may be used to planarize an uneven surface of asubstrate. Finally, the insulating layer may be thermally insulating toprotect the substrate from stress during some types of processing, forexample, when using lasers. The insulating layer 12 is selected fromdielectric materials such as, for example, but not limited by, siliconnitride, alumina, and silicon oxides. Additionally, layer 12 may act asa diffusion barrier to prevent the accidental doping of the activelayers. For various embodiments of photoconductive devices contemplatedthe insulating layer 12 is about 50 nm to about 100 nm in thickness.

In the absence of in situ processing, the step of fabrication ofembodiments of Group IV semiconductor thin film 19 in FIG. 2C fromembodiments of Group IV semiconductor nanoparticle compact 18 in FIG. 2Bis done in an inert, substantially oxygen free environment, usingtemperatures between about 100° C. to about 100° C., depending on thenature of the Group IV semiconductor nanoparticle, and fabricationprocess parameters, as will be discussed in more detail subsequently.Thin films may be processed in inert environments using a noble gas ornitrogen, or mixtures thereof, or they may be processed in vacuo.Additionally, to create a reducing atmosphere, up to 20% by volume ofhydrogen may be mixed with the noble gas, or nitrogen, or mixturesthereof. Though as previously discussed, “inert” is not limited inmeaning to substantially oxygen free, one metric of an inert environmentincludes reducing the oxygen content so that the Group IV semiconductorthin films produced have no more than about 10¹⁷ to 10¹⁹ oxygen contentper cubic centimeter of Group IV semiconductor thin film. Heat sourcescontemplated for use include conventional contact thermal sources, suchas resistive heaters, as well as radiative heat sources. Such radiativesources include, for example lamps, lasers, microwave processingequipment, and plasmas. More specifically, tungsten-halogen andcontinuous arc lamps are exemplary of radiative lamp sources.Additionally, lasers operating in the wavelength range between about 0.3micron to about 10 micron, and microwave processing equipment operatingin even longer wavelength ranges are matched to the fabricationrequirements of embodiments of Group IV semiconductor thin filmsdescribed herein. These types of apparatuses have the wavelengths forthe effective penetration of the targeted film thicknesses, as well asthe power requirements for fabrication of embodiments of Group IVsemiconductor thin films disclosed herein.

With respect to factors affecting the fabrication of a deposited GroupIV nanoparticle thin film into a densified thin film, the time requiredvaries as an inverse function in relation to the fabricationtemperature. For example, if the fabrication temperature is about 800°C., then for various embodiments of Group IV photoconductive thin films,the fabrication time may be, for example, between about 5 minutes toabout 15 minutes. However, if the fabrication temperature is about 400°C., then for various embodiments of Group IV photoconductive thin films,the fabrication temperature may be between about, for example, 1 hour toabout 10 hours. The fabrication process may also optionally include theuse of pressure of up to about 7000 psig. The fabrication of Group IVsemiconductor thin films from Group IV semiconductor nanoparticlematerials has been described in US Provisional Application; App. Ser.No. 60/842,818, with a filing date of Sep. 7, 2006, and entitled,“Semiconductor Thin Films Formed from Group IV Nanoparticles”. Theentirety of this application is incorporated by reference.

Regarding the coating 15 of FIG. 2A, one coating contemplated for use,and removed using in situ processing during Group IV semiconductor thinfilm fabrication from Group IV semiconductor nanoparticles, is an oxidelayer. As previously discussed, Group IV semiconductor nanoparticles arehighly reactive, and react with a number of species, such as oxygen andwater, to promote the formation of an oxide layer. It has been observedthat even under conditions considered inert for one of ordinary skill inthe art accustomed to the handling air-sensitive materials that a thinoxide layer may nonetheless form on the Group IV semiconductornanoparticles. This may be obviated by using more scrupulous conditionsfor excluding and scrubbing sources of oxygen in order to ensure thatthere is no more than about 10¹⁷ to about 10¹⁹ of oxygen per cubiccentimeter of a Group IV semiconductor thin film, as previouslydiscussed.

Alternatively, under inert conditions, a thin film of a silicon oxidefilm may be allowed to form as a coating over Group IV semiconductornanoparticles by controlling the concentration and time of exposure toan oxygen source. Such a thin film may not only provide stability forthe Group IV semiconductor nanoparticles, but may allow dispersion ofsuch particles in selected types of solvents, for example includingorganic solvent classes such as aromatic and aliphatic alcohols,ketones, aldehydes, and ethers, and mixtures thereof.

In FIG. 3A and FIG. 3B, two examples of embodiments of in situ processesuseful in the removal of an oxide layer from Group IV semiconductornanoparticles and thin films are shown which are exemplary renderingssolely the purpose of highlighting concepts of embodiments of in situprocesses for oxide layer removal from such materials, as previouslydiscussed. In the embodiment of an in situ treatment shown in FIG. 3A,process 20 is an in situ chemical vapor etching process to remove theoxide coat during the fabrication of a Group IV semiconductor thin film.In another embodiment of an in situ process 21 depicted in FIG. 3B, ashort exposure to a high-temperature in vacuo of the porous compactformed from oxide capped Group IV semiconductor nanoparticles is used toremove the oxide layer.

Regarding in situ process 20, one embodiment of a process for the insitu removal of an oxide layer formed on Group IV semiconductornanoparticles, as shown for porous compact 17 of FIG. 3A, is the use ofhydrofluoric acid (HF) chemical vapor etching. In addition to theremoval of the oxide layer, the HF treatment leaves the surface of theGroup IV semiconductor nanoparticles or thin films hydrogen-terminated,which as one of ordinary skill in the art is apprised, is desirable forstability and performance. Regarding the fabrication time andtemperature, an embodiment of a time/temperature profile 22 forfabrication process 20 is shown if FIG. 3A. During process phase thatincludes time t₁, a conditioning step is performed. Such a conditioningstep may be useful for driving off volatile chemical species, such assolvent, as well as assisting in making the porous compact 17 moremechanically stable. Such a step may be done for about 1 minute to aboutone hour, and between the temperatures of about 30° C. to about 300° C.in an inert environment, for example, either in the presence of an inertgas, or in vacuo. After the conditioning step at t₁, the temperature isramped to the targeted fabrication temperature t₂ for the thermalprocessing of Group IV semiconductor nanoparticle porous compact 18 toGroup IV semiconductor thin film 19, and held for the interval betweent₂-t₃. As previously discussed, the processing temperature for thefabrication of a Group IV semiconductor thin film from Group IVsemiconductor nanoparticles may be between about 100° C. to about 1000°C.; the selection of which is take in consideration of fabrication time.

Several embodiments of HF treatment for the in situ removal of an oxidelayer on Group IV semiconductor nanoparticles, as shown in FIG. 3A, arecontemplated. HF process profile 24 indicates an embodiment of a processprofile for the in situ treatment of the device to HF. The HF treatmentmay be done by exposure of a Group IV semiconductor porous compact tovapors from an aqueous solution of HF or may be done in the vapor phaseusing anhydrous HF (AHF) in conjunction with mixtures of other vapors.For example, in FIG. 3A, just at the end of the conditioning step, andbefore reaching the targeted fabrication temperature, at a time t₂, theporous compact 19 made of particles having an oxide layer could beexposed to vapors from an aqueous solution saturated with HF. Suchsolutions are about 49% (w/w) HF. For example, in reference to FIG. 2A,a 1″×1″ quartz substrate 10, coated with molybdenum layer 14 of about100 nm, having a porous compact 19 of about 1 micron in thickness ofGroup IV semiconductor nanoparticles may be placed in a small chamber.The chamber may be either a material having a fluorohydrocarbon coating,or of a ceramic material, with a volume of between about 50 cc to about500 cc, in which vapors from a solution of 49% (w/w) HF in water havebeen allowed to equilibrate. Exposure of such a sample to the aqueous HFvapors may be between about 2 minutes to about 20 minutes at chambertemperatures of between about 25° C. to about 60° C.

Alternatively, anhydrous HF (AHF) vapor with a controlled amount ofvapor from a low molecular weight protic solvent, such as water or a lowmolecular weight alcohol, such as methanol or ethanol, is allowed toflow into the fabrication chamber. The composition of such vapors canvary widely, where the vapor pressure of AHF may be between about 1 Torrto about to 20 Torr, while the ratio of partial pressure of the vaporsfrom the protic solvent to that of AHF may be range between about 0.02to about 0.7 Generally, the higher the amount of AHF vapor to that ofthe protic solvent (i.e the lower the ratio of protic solvent vapor toAHF vapor), the faster the etch rate. Additionally, etch rate isimpacted by the temperature at which the vapor etching is done. Giventhe reactivity of AHF, vapor etching temperatures may be done at betweenabout 25° C. to about 60° C. For embodiments of either the exposure of aGroup IV semiconductor thin film to vapors from an aqueous HF solutionsor using controlled vapor etching, the conditions for etching can beoptimized by observing the change in contact angle going from a highsurface energy oxide to a low surface energy semiconductor material.

With respect to embodiments of the HF process profile 24, as indicatedfor an exemplary embodiment of thin film fabrication method 20, the timefor introducing the HF may be done at a temperature below the targetedthermal processing temperature. In alternative embodiments of thin filmfabrication method 20, the onset of the introduction of the HF vapor mayoccur at various times during the device fabrication. For example, insome embodiments of device fabrication method 20, the HF vapor may beintroduced before any thermal processing is initiated in order toeffectively etch the oxide layer from Group IV semiconductornanoparticles in a porous compact 17, while in other embodiments the HFvapor may be introduced in the interval of the conditioning portion ofthe ramp. In still other embodiments, HF vapor may be introduced in thethermal processing step after densification has progressed. As one ofordinary skill in the art is apprised, other embodiments of processprofile 24 are possible by varying the time of introduction of the HFvapor, the total time of exposure of the thin films to the vapor, thetemperature of the processing profile that overlaps the HF exposure, andpartial pressure of the HF vapor in the processing gas.

Another embodiment for the removal of an oxide layer from Group IVsemiconductor nanoparticles is shown in process profile 21, depicted inFIG. 3B. In this exemplary embodiment, after a conditioning step t₁, asdiscussed above, except process profile is done in vacuo at betweenabout 1×10⁻⁷ to about 1×10⁻⁴ Torr. At t₂, the temperature is ramped tobetween about 300° C. to about 1350° C. for a short duration of betweenabout 0.1 minutes to about 10 minutes, or to process time t₃. In theinterval of time between t₂-t₃, the oxide layer decomposes. For example,in the case of silicon, it is believed to be removed as SiO_((g)).During this high temperature interval, the process of thermal processingof a porous compact 18 to a thin film 19 is initiated, and is completedduring a lower temperature interval between t₄-t₅ of longer durationthan the high temperature step. This interval may be at between about300° C. to about 800° C. for up to about 30 minutes. For either process20 of FIG. 3A or process 21 of FIG. 3B, at the end of the processprofile, after Group IV semiconductor thin film 19 has been formed, thethin film may be removed from the inert processing environment, asindicated in process step 150 of FIG. 1.

Cross-sections of renderings of a porous compact 37 and embodiments ofthin films 38, 39 having interstitial spaces 33 are shown in FIGS.4A-4C, which are renderings shown for the purpose of highlightingconcepts, and are not meant as actual representations of the thin filmmorphologies of embodiments of Group IV semiconductor thin filmsdisclosed herein. The considerations for the substrate 30, the firstelectrode 34, and the insulating layer 32 are the same as previouslydescribed for the substrate 10, the first electrode 14, and theinsulating layer 12 of FIGS. 2A-2C. In such an embodiment of a thin film38, the interstitial spaces 33 remain in fluid communication with theexternal environment. As can be seen by inspection of thin film 38, thefabrication process has produced a film in which there is continuous,isotropic electrical communication within thin film 38. It iscontemplated that a variety of fluids may be used to fill theinterstitial spaces 33 with an insulating material using in situtreatment during thin film fabrication. The insulating material becomesa solid which fills or essentially fills the interstitial spaces underthe targeted fabrication conditions for thin film 38. When theinterstitial spaces 33 are filled or essentially filled with aninsulating material, a continuous thin film 39 is formed, which will bea stable semiconductor thin film once transferred from an inertenvironment, as shown in process step 150 of FIG. 1.

In FIG. 5, an embodiment of thin film fabrication process 40 is shown inwhich in situ treatment of thin film 38 is done. In the exemplaryembodiment of thin film fabrication method 40 of FIG. 5, an embodimentof a thermal ramp profile 42, and an embodiment of the profile forintroduction of a fluid 44 are indicated. At the initial time, t₀,porous compact 37 having interstitial spaces 33 is deposited onsubstrate 30, and is ready for fabrication. In the second process step,at time interval including t₁, the sample is conditioned before thethermal processing of the porous compact to fabricate a photoconductivethin film 38. Such a conditioning step may be useful for driving offvolatile chemical species, such as solvent, as well as assisting inmaking the porous compact 37 more mechanically stable. Such a step maybe done for about 1 minutes to about one hour, and between thetemperatures of about 30° C. to about 300° C. in an inert environment,for example, such as in the presence of an inert gas, or in vacuo. Afterthe conditioning step, the temperature is ramped at t₂ to the targetedfabrication temperature of between 10° C. to about 1100° C. In theexemplary embodiment shown in FIG. 5, after the fabrication of thin film38 has been initiated, as shown at t₃, the introduction of a fluid isdone, as indicated by process profile 44.

It is contemplated that a variety of fluids may be suitable for use forthe purpose of the in situ filling or essential filling of interstitialspaces 33 with insulating material, such depicted in FIG. 4C. In someembodiments, the fluids are selected from gases, while in otherembodiments, the fluids are selected from liquids that may be readilyapplied, and readily wet the Group IV semiconductor nanoparticles orthin film, and hence penetrate into either the interstitial spaces of aGroup IV semiconductor porous compact or thin film. Depending on theprocess parameters, some embodiments of a Group IV semiconductor thinfilm 39 may be produced in which the interstitial spaces 33 are filled,such as the interstitial spaces in FIG. 4C with shading. In otherembodiments of a Group IV semiconductor thin film 39, voids 35 may existafter in suit filling of the interstitial spaces with an insulatingmaterial, but are no longer in fluid communication with the externalenvironment.

With respect to fluids selected from gases, insulating materials such asnitrides, oxides, and carbides of Group IV semiconductor materials maybe deposited using chemical vapor deposition (CVD) techniques. Forexample, nitride materials can be deposited from gas compositions ofammonia with a Group IV semiconductor precursor gas, such as silane,disilane, germane, digermane, any of their halide analogs, andcombinations thereof. Currently, there are numerous plasma enhanced CVD(PECVD) processes for the deposition of silicon nitride at reasonablylow temperatures (e.g. ca. 200° C.). The PECVD deposition of nitrides ofGroup IV semiconductor materials are useful for filling or essentiallyfilling interstitial spaces 33 shown in FIG. 4B with insulatingmaterial, as shown in FIG. 4C. The desired characteristic of the gascomposition is that it must be readily decomposed into a nitride ofGroup IV materials within the targeted temperature range forfabrication; or between about 100° C. to about 1000° C., as previouslymentioned. It should be noted that the gas composition is typicallymixed with an inert gas, for example, such as nitrogen, and noble gasesfor example, such as argon and helium, and combinations thereof. InPECVD processes, many variable may impact the silicon nitridedeposition, including, for example, partial pressures of Group IVsemiconductor gas, ammonia, and inert gases, the substrate temperature,and the density of reactive species in the plasma (see for example,“Plasma Enhanced Chemical Vapor Deposition of SiN-Films for Passivationof Three-Dimensional Substrates”, Orfert, M., and Richter, K.; Surfaceand Coatings Technology, 116-119 (1999) 622-628). Related CVD processesare known for the deposition of oxides and carbides of Group IVsemiconductor materials.

As indicated for an exemplary embodiment of thin film fabrication method40, the time for introducing the gas composition may be done during thetime interval of the thin film fabrication, as indicated at time t₃ inthe fabrication time interval t₂-t₄, as shown in FIG. 5. In alternativeembodiments of thin film fabrication method 40, the onset of theintroduction of the gas composition may occur at various times duringthe device fabrication. For example, in some embodiments of devicefabrication method 40, the precursor gas may be introduced beforethermal processing is initiated in order to fill the interstitial spacesof the porous compact, while in other embodiments the precursor gas maybe introduced in the interval of the conditioning portion of the ramp.In other embodiments, the gas composition may be introduced during theramp towards the fabrication temperature, which is a temperature belowthe targeted thermal processing temperature, but above the temperatureat which the precursor gas will decompose. In still other embodiments ofthin film fabrication method 40, the introduction of the precursor gasmay occur after the fabrication of the thin film 38 has been completed.Finally, when the interstitial spaces are filled or essentially filled,the conditions may be chosen so that optionally, a capping layer (notshown) of nitrides, oxides, or carbides of Group IV semiconductormaterial are formed on top of the fabricated Group IV semiconductor thinfilm 39. The thickness of layer such a layer may be up to about 500 nm.

In still other embodiments of fluids used to fill interstitial spaces 33of embodiments of porous thin films, such 38, as shown in FIG. 4B,solutions of insulators may be used to fill interstitial spaces 33. Forexample, there are many types of spin-on-glass (SOG) materials that haveexcellent properties for filling narrow, high aspect ratio spaceswithout creating voids, and have dielectric constants of between about 3to about 4. Such SOG materials are typically solutions of siloxanematerials, and may be readily applied to a fabricated film, such asGroup IV semiconductor thin film 38 of FIG. 4B. Solutions of SOGs areapplied using spin coating at about 3000 to about 4000 rpm, followed bya bake step of between about 80° C. to about 250° C. for between about 1minute to about 30 minutes. After the bake step, a cure step is done atbetween about 400° C. to about 600° C. for between about 30 minutes toabout 1 hour. The resultant film is a thin film, such as thin film 39 ofFIG. 4C, where the interstitial spaces 33 are filled or essentiallyfilled.

For many embodiments of thin film 39 of FIG. 4C, a residual layer ofinsulating material may be also be deposited as either a continuous orpartial layer on the top of the thin film, as previously discussed.Where multiple Group IV semiconductor layers are required to fabricate adevice, such a residual top layer of an insulating material would needto be removed. As one of ordinary skill in the art is aware, insulatingmaterials may be removed from Group IV semiconductor films usingprocesses with end point detection, such as chemical mechanicalpolishing (CMP), reactive ion etching, and reverse sputtering.Alternatively, a metal paste (typically silver or aluminum paste mixedwith glass frit) may be applied using a technique such as screenprinting. In general, after heating, the metal paste will cure andsubsequently penetrate though the residual top layer of an insulatingmaterial in order to connect with an underlying Group IV semiconductorlayer.

In FIG. 6A and FIG. 6B, another embodiment of an in situ treatment of aGroup IV semiconductor thin film is depicted. A section of a thin film39, such as shown in FIG. 4B, is shown in FIG. 6A and FIG. 6B. In thesection shown of thin film 39, an expanded depiction of the thin filmsurface 40, is shown. What is depicted in expanded view 40 is that onthe surface of a hydrogen-terminated Group IV semiconductor thin film,there are sites that are not hydrogenated 41, which are referred to asdangling bonds. Such dangling bonds are reactive, and implicated in thedegradation of Group IV semiconductor thin films. Dangling bonds mayoriginate from exposure of a hydrogen-terminated Group IV semiconductormaterials to degradative conditions, for example, to high temperatures,e.g. above about 300° C. In FIG. 6B, the alkylation of the thin filmsurface is shown, to produce a passivated thin film surface 42. It hasbeen observed that if Group IV semiconductor materials are passivated,as with a side variety of organic moieties, that degradation of suchmaterials is either slowed or halted. Such an in situ passivationtreatment of a Group IV semiconductor thin film could be done while thethin film is still in an inert environment as a part of fabrication step140 of FIG. 1. The passivation of a surface of a Group IV semiconductorthin film while in an inert environment would stabilize the thin filmfrom degradation, once exposed to normal environmental conditions, as instep 150 of FIG. 1.

It is contemplated that such an in situ passivation of a thin film couldbe done using a fabrication process such as shown in FIG. 7, in which athin film surface, such as thin film surface 40 of FIG. 6A could betreated to create an alkylated surface group 42 of FIG. 6B. For example,reactions considered for passivation of a surface such as thin filmsurface 40 of FIG. 6A may be done with chemical species selected from aseries low molecular weight organic hydrocarbon species, for example, ofbetween about C2 to about C6, having a terminal alkene or alkyne groupthat can undergo a hydrosilylation. Hydrosilylation is a reaction of anunsaturated group of an organic moiety with a surface Group IVsemiconductor group to create an alkylated surface species, such analkylated surface group 42 of FIG. 6B. The considerations for choosing acandidate hydrocarbon species include, but are not limited by, capableof providing high surface area coverage, and readily vaporized at thetargeted reaction temperatures and pressures. In some embodiments, wherecapping a dangling bond is desirable, the reaction conditions may be atabout room temperature and at about atmospheric pressure. In otherembodiments, where passivation of a potentially chemically reactivesurface is desirable, the reaction temperature may be at between 150° C.to 300° C., while the pressure may be between about 1 Torr to aboutatmospheric pressure. Examples of such hydrocarbon species include, byare not limited by, ethylene, acetylene, butene, and hexyne.

FIG. 7 is an embodiment of a thin film fabrication process 50, which isexemplary of a thin film fabrication process incorporating in situpassivation of a thin film surface. The steps for the fabrication ofthin film 38 are like those described for thin film process 40 of FIG.5. For thin film fabrication process 50, after the formation of thinfilm 38, an in situ passivation process step 54 is initiated at t₄. Aspreviously mentioned, a desired characteristic of embodiments of usefulhydrocarbon species is that they be in the gas phase within in atemperature range of between about 25° C. to about 300° C. Within thisrange, embodiments of the hydrosilylation reaction using an organichydrocarbon having a terminal alkene or alkyne group to passivate thesurface of a Group IV semiconductor material can be optimized. It shouldbe noted that the hydrocarbon species may be mixed with an inert gas,for example, such as nitrogen and hydrogen, and noble gases for example,such as argon and helium. In various embodiments of methods for the insitu passivation of Group IV thin films, the inert gas may be up toabout 99% in composition with the hydrocarbon species, and may bemaintained at between about 1 Torr to about one atmosphere and held atbetween about 25° C. to about 300° C. for between about 10 minutes oftime to 10 hours. In addition to resistive heat, the hydrocarbon gasesmay also be volatilized using sources such as lamps, for example,tungsten-halogen lamps and continuous arc lamps, lasers operating in thewavelength range between about 0.3 micron to about 10 micron, andmicrowave processing equipment. In that regard, the process ofpassivation of a the surface of a Group IV semiconductor thin film iscompatible with the previously discussed methods used for fabricatingphotoconductive thin films from films of deposited Group IVsemiconductor nanoparticles. After the completion of the passivationprocess step 54, the thin film may be removed from an inert environment,as indicated in step 150 of FIG. 1.

While principles of the disclosed in situ treatments during thefabrication of Group IV semiconductor thin films have been described inconnection with specific embodiments of thin films and methods, itshould be understood clearly that these descriptions are made only byway of example and are not intended to limit the scope of what isdisclosed. In that regard, what has been disclosed herein has beenprovided for the purposes of illustration and description. It is notintended to be exhaustive or to limit what is disclosed to the preciseforms described. Many modifications and variations will be apparent tothe practitioner skilled in the art. What is disclosed was chosen anddescribed in order to best explain the principles and practicalapplication of the disclosed embodiments of the art described, therebyenabling others skilled in the art to understand the various embodimentsand various modifications that are suited to the particular usecontemplated. It is intended that the scope of what is disclosed bedefined by the following claims and their equivalence.

1. A method of forming a densified nanopartiele thin film, comprising:positioning a substrate in a first chamber; depositing a nanoparticleink, the nanoparticle ink including a set of Group IV semiconductorparticles and a solvent; heating the nanoparticle ink to a firsttemperature between about 30° C. and about 300° C., and for a first timeperiod between about 1 minute and about 60 minutes, wherein the solventis substantially removed, and a porous compact is formed; positioningthe substrate in a second chamber, the second chamber having a pressureof between about 1×10⁻⁷ Torr and about 1×10⁻⁴ Torr; depositing on theporous compact a dielectric material; wherein the densified nanoparticlethin film is formed.
 2. The method of claim 1, wherein the dielectricmaterial is one of a nitride material, an oxide material, and a carbidematerial
 3. The method of claim 1, wherein the set of Group IVsemiconductor particles is one of n-doped semiconductor particles,p-doped semiconductor particles, and intrinsic semiconductor particles.4. The method of claim 1, wherein the substrate is one of silicon,quartz, soda lime, and borosilicate glasses.
 5. The method of claim 1,further including the step of positioning the substrate in a thirdchamber, after the step of depositing a dielectric material.
 6. Themethod of claim 5, further including the step of substantially removinga residual top layer of the dielectric material using one of a chemicalmechanical process, a reactive ion etch process, and a reversesputtering process, after the step of positioning the substrate in athird chamber.
 7. The method of claim 6, further including the step ofdepositing a conductive material on the porous compact in order to forman electrode, after the step of substantially removing a residual toplayer of the dielectric material.
 8. The method of claim 7, wherein theconductive material comprises at least one of aluminum, silver,molybdenum, chromium, titanium, nickel, and platinum.
 9. The method ofclaim 5, further including the step of depositing a metal paste on aresidual top layer of the dielectric material, after the step ofpositioning the substrate in a third chamber.
 10. The method of claim 9,further including the step of heating the metal paste such that themetal paste penetrates the residual top layer causing an electrode toform on the densified nanoparticle thin film, after the step ofdepositing a metal paste on a residual top layer of the dielectricmaterial.
 11. A method of forming a densified nanoparticle thin film ina chamber, comprising: positioning a substrate; depositing ananoparticle ink, the nanoparticle ink including a set of Group IVsemiconductor particles and a solvent; densifying the nanoparticle inkinto a porous compact, wherein the solvent is removed; spin coating aspin-on-glass material on the porous compact from about 3000 rpm toabout 4000 rpm; heating the spin-on-glass material to a firsttemperature between about 80° C. and about 250° C., and for a first timeperiod between about 1 minute to about 30 minutes; heating thespin-on-glass material to a second temperature between about 400° C. andabout 600° C., and for a second time period between about 30 minute toabout 1 hour; wherein the densified nanoparticle thin film is formed.12. The method of claim 11, wherein the set of Group IV semiconductorparticles is one of n-doped semiconductor particles, p-dopedsemiconductor particles, and intrinsic semiconductor particles.
 13. Themethod of claim 11, wherein the substrate is one of silicon, quartz,soda lime, and borosilicate glasses.
 14. The method of claim 11, furtherincluding the step of depositing a conductive material on the porouscompact in order to form an electrode, after the step of substantiallyremoving a residual top layer of the dielectric material.
 15. The methodof claim 14, wherein the conductive material comprises at least one ofaluminum, silver, molybdenum, chromium, titanium, nickel, and platinum.16. The method of claim 11, further including the step of depositing ametal paste on a residual top layer of the dielectric material, afterthe step of positioning the substrate in a third chamber.
 17. The methodof claim 16, further including the step of heating the metal paste suchthat the metal paste penetrates the residual top layer causing anelectrode to form on the densified nanoparticle thin film, after thestep of depositing a metal paste on a residual top layer of thedielectric material.
 18. A method of forming a densified nanoparticlethin film in a chamber, comprising: positioning a substrate; depositinga nanoparticle ink, the nanoparticle ink including a set of Group IVsemiconductor particles and a solvent; densifying the nanoparticle inkinto a porous compact, wherein the solvent is removed; depositing ahydrocarbon species on the porous compact, wherein the hydrocarbonspecies includes one of a terminal alkene group or a terminal alkynegroup; heating the hydrocarbon species to a first temperature betweenabout 150° C. and about 300° C., at a pressure of between about 1 Torrand about an atmosphere; wherein the densified nanoparticle thin film isformed.
 19. The method of claim 18, wherein the set of Group IVsemiconductor particles is one of n-doped semiconductor particles,p-doped semiconductor particles, and intrinsic semiconductor particles.20. The method of claim 18, wherein the substrate is one of silicon,quartz, soda lime, and borosilicate glasses.
 21. The method of claim 18,wherein the hydrocarbon species is one of ethylene, acetylene, butane,and hexyne.
 22. The method of claim 18, further including the step ofdepositing a conductive material on the porous compact in order to forman electrode, after the step of substantially removing a residual toplayer of the dielectric material.
 23. The method of claim 22, whereinthe conductive material comprises at least one of aluminum, silver,molybdenum, chromium, titanium, nickel, and platinum.
 24. The method ofclaim 18, further including the step of depositing a metal paste on aresidual top layer of the dielectric material, after the step ofpositioning the substrate in a third chamber.
 25. The method of claim24, further including the step of heating the metal paste such that themetal paste penetrates the residual top layer causing an electrode toform on the densified nanoparticle thin film, after the step ofdepositing a metal paste on a residual top layer of the dielectricmaterial.